The invention concerns a tool-magazine mechanism for a tool machine in which at least one tool magazine carries several tools. A tool gripping device individually receives the tools from the tool magazine and transports them to a tool mounting fixture for the tool machine.
Tool-magazine mechanisms are especially known on numerically controlled tool machines in many design forms. Their purpose is to keep several, different tools ready for an automatically controlled tool exchange.
It is common to all magazine devices for the type mentioned at the outset that each of the tools carried in the magazine mechanism can be taken over directly by the tool gripping device. In order to achieve this, the tool magazine is usually arranged movably on the tool machine, for example in a swivelable manner and/or transportable, so that each individual tool storage position of the magazine can be brought into a position accessible to the tool gripping device. Either the tools and/or the storage positions assigned to them are coded, so that the selection of the tools to be taken over by the tool gripping device can take place automatically by a control mechanism.
The requirement is increasingly made in manufacturing techniques to control machine tools automatically over long periods of time, without the intervention of operating personnel being required. This requirement results especially from the effort to automatically operate tool machines in a controlled manner in manufacture during a work shift, especially the night shift.
Achieving of this desire is complicated by the fact that the tool service life, that is to say the time between two successive tool changes in most cases, is much less than the length of a working shift, and indeed primarily it is determined by tool wear.
There are different possibilities for monitoring the service life of tools, for example by a direct wear measurement on the tool, or by a running tool control, or by cutting force measurements during the processing procedures. If it is determined in this manner that a tool change is required, up to now, in most cases, the tool machine is maintained stationary and a signal is given, which shows an operational or monitoring person that a tool change must be made.
The possibilities for an automatic tool change were very limited by the design characteristics of the known tools and tool magazines. Basically, it was possible to carry the tools in several storage positions of the tool magazine, which could be used in succession. The effort for coding, control and monitoring, however, was relatively high, since every individual tool or every individual storage position in the tool magazine had to be coded. Moreover, in many cases, the capacity of conventional tool magazines does not suffice for conducting the worn-out tools back into the tool magazine.
If the coding is limited to individual storage positions of the tool magazine, the danger exists that the correctly coded storage position might be equipped with the wrong tool, the use of which could lead to serious damage. On the other hand, if each individual tool was coded, then it could be determined before the use of the tool whether the coding present on the tool corresponds with the tool coding actually required for control. However, coding of each individual tool proves to be all the more difficult and expensive, the less room there is available for this on the tool. On the other hand, for several reasons, the effort is being made to keep the tools to be exchanged as small as possible and to keep their design as simple as possible. However, these efforts are contrasted with the necessity of coding each individual tool.
On conventional tool-magazine mechanisms on tool machines, the change-over for machining another workpiece involves great effort, because in general all tools present on the tool magazine must be removed and the tool magazine must be reloaded, due to which a relatively long shutdown time of the machine is caused. In the given case, a coding of the individual storage places of the tool magazine on the tool machine must take place due to which the required time expenditure is greatly increased.
Thus, it is the object of the invention to create a tool-magazine mechanism of the type named at the outset, which makes possible a simple tool change with little design effort and work expenditure, and without the intervention of operational personnel with the automated production work cycle, and which provides a rapid and simple change-over for the machining of different tools.
This object is solved according to the invention by the fact that the tool magazine is a separate constructional unit which can be removed from the tool machine, and that several similar tools can be carried in the tool magazine and shifted lengthwise by means of a driven feed mechanism. Thus, the entire magazine mechanism of the tool machine exhibits one or preferably several individually removable tool magazines. Since all tool magazines can be removed individually, several similar tools can be exchanged in a simple manner with a change-over to machining, without it being necessary to remove the tools individually from the magazine storage places and to re-equip the magazine. The machine design is essentially simplified by the fact that all magazine storage positions are no longer attainable for the tool gripping device nor do they need to be moved into the access area of the tool gripping device. Since the individual tools can be shifted longitudinally in each of the tool magazines, it is sufficient for each tool magazine which contains similar tools to provide an individual delivery place on the tool gripping device, without a movability of the tool magazine being required.
In especially advantageous designs of the concept of the invention, it is provided that each tool magazine exhibits a coding carrier, the coding of which identifies the tools. The coding can be detected by a coding reader arranged on the magazine receiving fixture of the tool machine and can be conducted to a control mechanism. In this way, a substantial increase of work safety is achieved with automated operating cycle, because neither a coding of each individual tool is required nor a coding of the magazine storage positions on the machine. Rather, it is sufficient to code the tool magazine carrying the individual tools or several tools of the same kind which can be used arbitrarily in the coded permanent receiving places on the machine. The coding of the individual tool magazines takes place outside of the tool machine in the framework of production preparation and therefore can be carried out without time pressure and with great reliability, due to the possibility of controls. The required shutdown times of the tool machine are substantially reduced, especially with the change-over for other workpieces, because it is no longer necessary to equip individual magazine storage positions, since only the individual complete tool magazines must be exchanged.
Even if the tool magazines are used in other than the provided arrangement and sequence, working errors of the tool machine are ruled out, because the coding readers arranged on the magazine receiving places obtain information about such use and identify to the control which tools are available on the concerned magazine uptake places. The control device then can appropriately control the movement of the tool gripping device or the magazine fixtures.
In an especially simplified design form of the invention, it is provided that the feed mechanism exhibits at least one feed comb which can be shifted lengthwise in the tool magazine, whose comb teeth can be moved in and out of mesh between the individual tools arranged in the lengthwise guide track transverse to the lengthwise guide track. At the same time, the feed comb transports all tools and thereby maintains their mutual correlation.
Advantageously, a stop comb can be shifted in the tool magazine only transverse to the lengthwise guide track, whose comb teeth are actually movable in and out of engagement between the tools arranged in the lengthwise guide track. This stop comb makes sure that the mutual correlation of the individual tools taken-up in the lengthwise guide track is maintained reliably even when the feed comb is out of mesh with the tools. There is also the transverse movement of the feed comb and of the stop comb preferably in synchronism.
An especially advantageous design is characterized by the fact that two parallel lengthwise guide tracks lying next to each other are provided in the tool magazine. While one of the two lengthwise guide tracks contains the new tools standing ready for the tool change, the actually used-up and replaced tools can be taken-up in the second lengthwise guide track. The transport process in each individual tool magazine is especially simple, because the shoving back of an expended tool corresponds to the shoving forward of a new tool. Thus, it is possible in a very simple design manner to connect both feed combs coordinated to both guide tracks with each other in a rigid manner and to drive them together.
The adherence of the intervals between the individual tools in those time intervals in which the feed comb is disengaged from the tools can also take place by spring-loaded stop mechanisms, which actually mesh with the individual tools. Then no stop comb is necessary. The feed comb can rest in the removable tool magazine or on at least one of the several magazine mounting places in the tool machine. When the feed comb rests in the tool magazine, the drive mechanism for the feed comb can rest either in each individual tool magazine or in turn, on at least one of several magazine mounting places of the tool machine.
Different movement cycles and drive types are possible for the movement of the comb teeth in and out of engagement with the tools. The feed comb can also be driven in a lengthwise movement and a transverse movement. When the comb teeth exhibit an abutting surface for the tools sloping in a common direction, and in transverse direction are supported in a spring-loaded manner either individually or in common, the transverse movement can be carried out automatically in the case of a withdrawal movement of the feed comb.